Errors of Electrolyte Level Analysis Caused by In-vitro Hemolysis

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Jinda Saisuksa-ard
Yosavee Chotchuang


Background: In-vitro hemolysis of serum specimen is commonly found and may change the serum electrolyte values. Repeated phlebotomy is usually required and the patient could have delayed treatment.
Objective : To compare serum electrolyte values between serum with and without hemolysis, and formulate an equation to correct the errors.
Material and method : A comparative analytical study was conducted on 75 patients admitted in medical wards of Lampang Hospital and had blood sampling for electrolyte analysis. The study group was 50 serum specimens with hemolysis 1+ and 25 specimens with hemolysis 2+ The control group was 75 non-hemolyzed specimens from the same patients within 4 hours
after notification of hemolysis. The data was analyzed by paired t-test and regression analysis.
Results : Serum potassium in hemolyzed samples were higher than non-hemolyzed samples significantly (4.68±1.24 mEq/L vs 3.82±0.98 mEq/L, p<0.001) but serum sodium (135.31±7.54 mEq/L vs 136.51±7.17 mEq/L, p<0.001) and chloride were lower (98.81±10.24 mEq/L vs 100.02±10.01 mEq/L, p=0.001). Serum bicarbonate was not significantly different (21.80±5.35 mEq/L
vs 22.29±5.23 mEq/L, p=0.136). The correction equation for serum potassium in hemolysis 1+ and 2+ were y = 0.62x + 1.75 and y = 0.62x + 1.11 respectively.
Conclusion : The significant higher level of serum potassium and lower sodium and chloride were found in hemolyzed specimens. We can calculate the corrected potassium value by the formulated equation and do not require re-sampling specimens.

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How to Cite
Saisuksa-ard , . J. ., & Chotchuang , Y. (2022). Errors of Electrolyte Level Analysis Caused by In-vitro Hemolysis. Lampang Medical Journal, 31(2), 75–82. Retrieved from
Original Article


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